Battery adapter



p 21, 1948. R. 1.. EICHBERG ET AL 9,

BATTERY ADAPTER Filed Nov. 23, 1944 Fig.l

ROBERT L. ETOHBERG HOMER R. MONTAGUE Patented Sept 2 1 194g UNITED STATES PATENT OFFICE 2,449,550 BATTERY marine Hebert clearin Arlinjgitii, Va. and Homer R.'Mo 1ita gue, Washington, D. 0.; Application November 23, 1944, Serial No. 5154,89ll 2 Claims. (01. item-13") (Granted. under the: act .11: March: 3, 1883, as amended April so, 1928; are 75v) The invention described herein may be manufactured and used by or for the Government: for governmental purposes, without the payment to us of any royalty thereon.

This invention relates to power supplies of the type utilizing. conventional-dry cell batteries; and more particularly to supplies, such as the filament supply for a small radio set, which involve current drains of such magnitude that conventional sizes of flashlight cells do not provide an adequate operating life between changes. of bat.- teries.

In a particular type of transceiver whichhas become popularly known as the handle-talkie due to its general resemblance to the handset of a conventional desk telephone, the filament. volt-- age required is 1.5 volts; that is thenominal voltage of an ordinary sal-ammoniac dry cell; The current drain of such as set, however, is or such magnitude that a single cell of flashlightqsiae (about 1%, inches in diameter and 2 inches long) would not provideadequate operating life before replacement. Thus, the operation of changing filament batteries becomes anunreasonable burden: upon the operator of such equipment, and results infrequent interruptions to communication.

The obvious solution to this problem, that is, to use a larger filament battery, i precludedinsofar as small portable devicesare concerned, by the fact that the next larger battery which; is sufficiently well distributed to facilitate supply, is about 2 inches indiameter and 6- i-nches long and weighs over 2 pounds. This size and weight is clearly intolerable in equipment intended for maximum portability.

Designers of small radio sets, faced with this situation, have been forced to adopt the expedient of utilizing a single cell l volt) filament battery of intermediate size. Thfac't' thatsuch a battery is of an unusual size not adapted for general use has the efiect of increasing its cost, as well as of rendering it relatively difiicult to obtain at the point of use. In the example unoer consideration, the diameter of this. flattery is the same as that of an ordinary flashlight cell, but its length is about 2 /2 times as great.

It would clearly be desirable to avoid the use of such a special battery in favor of the cheap, mass-production, widely distributed flashlight cell referred to in the second paragraph of this specification, and. particularly if this could be accomplished without modification of existing equipment designed to use the expensive, special, intermediate size of battery.

. design that it will be economical to produc jand substantially foolproof in operation. we accomplish this by an adapter designed to hold two ordinary flashlight cells in coaxial positions, but so constructed as toc'onnect the two electrically in parallel. By proper design, matters can be so arranged that the electrical terminals of such a device are located precisely" where they would be :11: the single, special size battery referred to above were to be used; also, it is possible to so design the adapter that the complete assembly has a diameter only slightly largerthan" that of the special battery it replaces. Thus, the assem bly can be substituted for the special battery without. any modification of the equipment into which it is inserted, and can be refilled when fresh. batteries are required.

our invention will be best understood by're'ference to the accompanying drawing illustrating one embodiment of our invention, and in which Figure 1' is. a perspective view of a complete adapter, Figure 2. is a sctionalview taken on liner-2 of Figure 1, Figure 3 is a partial sectional view takenwonline 3--3of Figure l, and Figure 4 is'an elevation View of the; complete device, with a pair ofordinary flashlight cells, shown by dash lines, in their properpositionsz' l Referring now to Figure 1' of the drawing, the numeral I designates a short cylindrical piece of an insulating material such as Bakelite, having tWooppositeI sides provided with fiat portions forming seats 2 and 3. Rigidly secured to the seat 2; asq y rivets Hl, is an elongated narrow member 4 of: springy. electrically conducting material such as metal, having turned-down ends 6 and 1 End 6; has. a centrally-located struck-up dimple 8, more clearly shown .inFi gure 2, while end .1 has a similar dimple I61 as shownin Figure 4, The ends 6 and 1 are similar, except that the dimpleli'opens downwardly in Figure 4, while dimple It opens upwardly in that'figure. p M

Rigidly secured in seat 3 of member I is a second elongated member 5 also of springy conducting material and having turned-up ends. 9 and Il. Each of these end pieces has an opening such as that designated by l3 in Figure 1, bounded on two sides by rows of teeth I 4 which extend at right angles to the surface of such end pieces.

The length of members 4 and 5 and the length of member I are so chosen that the space between the inner surface of dimple 8 and the outer edge of the teeth I4 on end piece 9 is just suflicient to permit an ordinary flashlight cell 20 (shown in dash lines in Figure 4) to be inserted there-.

between, with its cap terminal (positive) held between the walls of dimple 8, and its fiat bottom terminal (negative) in contact with teeth I4. Suflicient exial pressure is present to retain the cell in that position.

Similarly, a second flashlight cell can be inthe positive terminals of both flashlight batteries are connected together by member 4, as are their negative terminals by member 5. .A lso,1it Will be J observed that the outer surface of dimple Bacts 1 as a central positive terminal for connecting the assembly into adevice adapted to take an elongated size of dry cell, While the outer surface of I end piece I I is located precisely where the negative terminal (the bottom of the zinc can) of such a cellw-ould be.

Members 4 and 5 may be somewhat bowed transversely of their length, as shown in Figure l, to minimize the dilametral space occupied by contact than would a mere roughened flat surface. Second, these openings minimize the danger of inserting one of the cells in the wrong orientation, since the flat cap such as 22 in Figure 4 will not make positive contact with the edges of 7 opening I3. Reversal of one of the cells would of course result in'a large circulating current which would soon destroy both cells. Third, the provision of an opening 13 in end piece 9 permits the introduction of la mandrel into bore I5 (Figure 3) for (facilitating the riveting of members 4 and 5 to member I. Without this opening I3, the assembling of such members would be quite difficult and expensive, since both ends of bore I5 would be obstructed by the inner turnedover ends of elements 4 and 5.

The provision of open-ended dimples 8 and I6 rather than simple depressions to receive caps 22 of the flashlight cells, greatly increases the ease with which the latter can be inserted and removed from the adapter, without unduly increasing the risk of the cells slipping out by accident.

It'is obvious that either or both of members 4 and 5 can be coated lengthwise with a suitable insulating material if the adapter is to be used in locations where external contact to such members is undesirable.

It will be seen from the above description that we have devised an extremely simple device, having only 3 principal parts, which performs the function of holding two dry cells securely in coaxial relationship, connects them electrically in parallel without the use .of additional parts, is cheap to produce, foolproof, in operation, and is of substantially the same dimensions as the special-purpose battery which is to be replaced.

The reference herein to specific applications of our device, for instance to radio sets, is not to be construed to limit the device to such uses, since it may be utilized wherever it is desired to build up large capacity batteries from small cells.

We claim. 1. In a battery adapter for holding a plurality of cells in parallel electrical connection, a short central mounting member of insulating material, a pairo f elongated, electrically conductive straps, each having a bent-over portion at each end, and means for securing said straps to different'faces of said mounting member so that the four bent-over ends lie substantially along a common axis with the inner face of one end of each strap lying adjacent to, and facing, one end of the mounting member, one bent over' portion of each strap having a medial opening therein to prevent improper orientation of the cells.

.2. A device as covered by claim 1, in which the mounting member is of cylindrical shape having a central bore, and in which the bent-over ends of one strap have each a struck-up dimple, and the bent-over ends of the other strap have each 'a medial opening bordered on opposite edges by rows of teeth directed normal tothe planes-of said openings.

3. A battery adapter for holding a plurality of cells in parallel electrical connectionv having in combination a short solid cylindrical mounting member of relatively stiff and inflexible insulating material and having an axial bore therethrough, a pair ofielectrically conductingstraps, each of said straps having an end thereof mounted on an opposite face or said cylindrical member, one endof each of said straps'being'bentover an end of said cylindrical member, said strap ends being formed with aslot therein aligned with the bore of said cylindrical member, said slot being bordered with upstanding teeth, the other end of each of said straps being'b'ent over and provided with a raised channel to receive the center electrode of a drycell, the four bent over ends lying along a common axis. Q 1

ROBERT L. EICI-IBERG. HOMER R. MONTAGUE.

REFERENCES CITED The following references flle of this patent:

are of record in ,the

UNITED STATESPA'IENTS Y 7 fz,377,1 e1 fLe Strange May 29, 1945 

